Dark matter

39 ancestors of massive elliptical galaxies discovered in the early universe

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An article published in the journal “Nature” reports the discovery of 39 galaxies in the early universe. A team of researchers combined data from different telescopes to identify a group of galaxies dating back to the first two billion years after the Big Bang that were invisible to previous observations in their areas conducted at optical frequencies. Their study could offer new information on the evolution of galaxies, on the supermassive black holes at their center and also on the distribution of dark matter.

A measurement of the Hubble constant based on quasars suggests possible changes to cosmological models

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An article published in the journal “Nature Astronomy” describes the use of quasars as cosmic tracers to measure the expansion of the universe up to 12 billion years ago. Guido Risaliti of the University of Florence and Elisabeta Lusso of Durham University studied the X-ray and optical emissions of a number of quasars using the comparison between those emissions to accurately assess their distances. The results could explain the discrepancies between the different measurements carried out with other methods suggesting that the density of the mysterious dark energy isn’t constant over time.

A verification of dark matter heating

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An article published in the journal “Monthly Notices of the Royal Astronomical Society” reports confirmations to the hypothesis of the effect known as dark matter heating. A team of researchers looked for the effects of the presence of dark matter in dwarf galaxies relatively close to the Milky Way, finding the confirmation that star formation can heat it causing it to move outwards. It’s a new possibility to study dark matter to try to understand its nature.

The Abell S1063 galaxy cluster (Image NASA, ESA, and M. Montes (University of New South Wales, Sydney, Australia))

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An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes a new method to detect and map the dark matter existing in galaxy clusters with a higher precision than those used so far. Mireia Montes of the University of New South Wales, Australia, and Ignacio Trujillo of the Canary Islands Institute of Astronomy, Spain, exploited the so-called intracluster light, the faint light within galaxy clusters produced by their interaction, detected in the Hubble Frontier Fields program, to map the distribution of dark matter within them.

The galaxy cluster Abell 370 (Image NASA, ESA, A. Koekemoer, M. Jauzac, C. Steinhardt, and the BUFFALO team)

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The first Hubble Space Telescope’s observations in the new BUFFALO project have been published. Its goal is to shed light on the evolution of the first galaxies of the universe, also to establish the most interesting observation targets for the James Webb space telescope. The Abell 370 galaxy cluster is the first to be studied for this new survey together with a series of galaxies seen through gravitational lenses.